Defi is not a scam, just that those who are not try it before look at it as a scam. it's not good to hold your coins long in Defi, because the price can drop at anytime.
I think Defi is a bubble and can explode at any moment. However, it cannot be denied that Defi projects are a trend that is trusted by most investors and will certainly attract a lot of investors in the near future. At first, I thought very negatively about the Defi projects but now things are different and just spend a little time researching on that project you can make twice as much profit in short time.